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  • #76
    Originally posted by MidwestCamper View Post
    I'm not an electrician but feel the chassis ground method as described in the article on the TV should be avoided. If the heavy ground cabling fails, the current will take the next best path to the ground wire in the 7 way connector and with a 60amp DCDC this could be an issue. As much as copper costs these days, I would still run a dedicated positive and negative cable from the TV battery to the DCDC. Its important to pull from the battery since many TV applications use a current meter to determine actual SOC and load of the TV battery.

    Jim
    Hi, I'm new and just stumbled on this article while looking for Solar info. Funny, I'm just completing the install of my DC-DC charger and found this fascinating to compare my install to. In my process I did a lot of independent research and had many email exchanges with Renogy, Denso and my Victron Rep. If there is interest, perhaps I'll post my install process which did deviate from what howson and Yoda did.

    For the benefit of the larger group and to provide a different perspective I did attach my grounding to the chassis at the rear of the TV. I thought about this quite a bit and finally concluded that, since the truck wiring is doing this everywhere, it must be OK to do. I think it really comes down to how one does the grounding and where attach point is. Like another post here I used a grinding tool to carefully remove all paint and I used a copper washer between the lug and frame to ensure a good contact. I also used a substantial self drilling screw with a lock washer. This is all very similar to what the truck maker did when grounding directly from the battery to the frame. For good measure I intend to cover the connection with liquid electrical tape. I can't imagine this ever failing. Moreover I believe the Renogy negative input terminal from the TV is electrically protected from the negative output connection to the Trailer (they are independent connections after all). This would imply that, even if the ground failed, the DC-DC converter would disconnect well before the 7-way connector wire overheats and melts.

    For me the biggest concern is protection of the TV alternator. In my case the OEM alternator (2021 Jeep GC) is made by DENSO. The alternator states 230A but the reality is that this spec is tied to a specific RPM and the available amps drops with RPM. Although unconfirmed I was informally told the 230A is rated at 2000 RPM (I could not get it documented though). My concern is whether running at idle for extended periods the DC-DC converter will cause the alternator to overheat. That is, what the continuous use alternator is rating is at, say, 750 RPM. I had purchased both the 40A and 60A Renogy converters (Amazon had a low price on both) intending on returning the 60A if it was too much.

    One would think this would be straightforward to figure out. But that is not the case. I couldn't get any decent technical information from either Chrysler or Denso. On the other hand Renogy assured me there would be no issue at all but with no substantive technical information to backup that claim. The poor English from the representative I was emailing back and forth with eliminated my confidence in their claim (offshore help?). In the end I ran a thermal test measuring the alternator temp while charging my battery bank and feel somewhat comfortable that the 72A or so being drawn from the alternator while feeding the ~60A to the Trailer batteries would not cause an issue at idle. When I get some free time I'll try to post the results of that test in case others can benefit. However, I'd love to see if anyone else running the 60A DC-DC converter had alternator concerns and how they alleviated them.
    Earl
    2022 Imagine 22RBE
    2021 Jeep Grand Cherokee (5.7L V-8 MDS VVT)
    Anderson 3350 WDH w/ Redarc TowPro EBRH-ACCV3

    Comment


    • #77
      Originally posted by TravelHabit View Post

      ...
      perhaps I'll post my install process which did deviate from what howson and Yoda did.

      ...
      I'd be very interested in how you did the install. Please post.

      -Steve
      Last edited by howson; 11-27-2021, 04:32 PM.
      2018 Solitude 310GK, disc brakes
      Morryde SRE4000/XFactor with heavy duty shackles, V-Brackets in spring hangers
      2012 Ram 3500 SRW 6.7 Diesel, air bags
      18k B&W Companion, non-slider
      640 watts solar, 400 amp-hour Lion Safari UT 1300 battery bank
      Aims 1500 watt inverter/charger with ATS
      Somerset, WI

      Comment


      • #78
        Originally posted by TravelHabit View Post

        Hi, I'm new and just stumbled on this article while looking for Solar info. Funny, I'm just completing the install of my DC-DC charger and found this fascinating to compare my install to. In my process I did a lot of independent research and had many email exchanges with Renogy, Denso and my Victron Rep. If there is interest, perhaps I'll post my install process which did deviate from what howson and Yoda did.

        For the benefit of the larger group and to provide a different perspective I did attach my grounding to the chassis at the rear of the TV. I thought about this quite a bit and finally concluded that, since the truck wiring is doing this everywhere, it must be OK to do. I think it really comes down to how one does the grounding and where attach point is. Like another post here I used a grinding tool to carefully remove all paint and I used a copper washer between the lug and frame to ensure a good contact. I also used a substantial self drilling screw with a lock washer. This is all very similar to what the truck maker did when grounding directly from the battery to the frame. For good measure I intend to cover the connection with liquid electrical tape. I can't imagine this ever failing. Moreover I believe the Renogy negative input terminal from the TV is electrically protected from the negative output connection to the Trailer (they are independent connections after all). This would imply that, even if the ground failed, the DC-DC converter would disconnect well before the 7-way connector wire overheats and melts.

        For me the biggest concern is protection of the TV alternator. In my case the OEM alternator (2021 Jeep GC) is made by DENSO. The alternator states 230A but the reality is that this spec is tied to a specific RPM and the available amps drops with RPM. Although unconfirmed I was informally told the 230A is rated at 2000 RPM (I could not get it documented though). My concern is whether running at idle for extended periods the DC-DC converter will cause the alternator to overheat. That is, what the continuous use alternator is rating is at, say, 750 RPM. I had purchased both the 40A and 60A Renogy converters (Amazon had a low price on both) intending on returning the 60A if it was too much.

        One would think this would be straightforward to figure out. But that is not the case. I couldn't get any decent technical information from either Chrysler or Denso. On the other hand Renogy assured me there would be no issue at all but with no substantive technical information to backup that claim. The poor English from the representative I was emailing back and forth with eliminated my confidence in their claim (offshore help?). In the end I ran a thermal test measuring the alternator temp while charging my battery bank and feel somewhat comfortable that the 72A or so being drawn from the alternator while feeding the ~60A to the Trailer batteries would not cause an issue at idle. When I get some free time I'll try to post the results of that test in case others can benefit. However, I'd love to see if anyone else running the 60A DC-DC converter had alternator concerns and how they alleviated them.
        TravelHabit If you can wire a fully isolated DCDC with a dedicated ground, you may be ok but depending in how for instance a three wire system is used, it may be best to disconnect the 7 way ground and use a heavy ground cable for the DCDC as well as other functions such as lights and so on. If there is a failure on the heavier wire, the return will be sought out through the lighter wire if the two systems share a ground. My 4 wire Renogy is wired as a three wire with a single ground path back to the TV.
        For the alternator, I inquired with Denso directly as a systems engineer in the auto industry and while I cannot share detailed information, I can share their concern with high draw at idle with a lithium battery connected to a TV depending in how the system is calibrated. From my own past experiences as a calibrator, smart alternators today are NOT calibrated by folks working with a trailer connected with a lithium battery bank, so I would not assume that because your alternator may be running cooler on the surface, it has relevance to all the other systems out there. Also the diodes in the rectifier bridge of your alternator would be a better focus rather than the surface temperature of the alternator housing. The other issue with grounding high current devices to the frame is the manufacturer has not approved or tested this so it would be best to run a dedicated ground and feed directly from the TV battery. Many modern systems will model the battery SOC or can also measure it through an open voltage check in addition to using a current probe during operation to monitor useage. So the OEM system is designed to be operating directly to and from the TV battery. There are almost infinite ground locations for components throughout the system, but each of these are signed off by the design responsible engineer. If in doubt, and without having engineering approval, run both leads directly to the TV battery.

        Here is an interesting article that explains the use of a IBS that is commonly used on today's systems. The IBS is located on the negative battery terminal which will provide some relevance to connecting outside devices to the TV.

        https://www.batterypoweronline.com/a...otive-designs/

        Jim
        Last edited by Guest; 11-27-2021, 04:35 PM.

        Comment


        • #79
          Originally posted by MidwestCamper View Post

          TravelHabit If you can wire a fully isolated DCDC with a dedicated ground, you may be ok but depending in how for instance a three wire system is used, it may be best to disconnect the 7 way ground and use a heavy ground cable for the DCDC as well as other functions such as lights and so on. If there is a failure on the heavier wire, the return will be sought out through the lighter wire if the two systems share a ground.
          For the alternator, I inquired with Denso directly as a systems engineer in the auto industry and while I cannot share detailed information, I can share their concern with high draw at idle with a lithium battery connected to a TV depending in how the system is calibrated. From my own past experiences as a calibrator, smart alternators today are calibrated by folks that do not work with a trailer connected with a lithium battery bank, so I would not assume that because your alternator may be running cooler on the surface, it has relevance to all the other systems out there. Also the diodes in the rectifier bridge of your alternator would be a better focus rather than the surface temperature of the alternator housing. The other issue with grounding high current devices to the frame is the manufacturer has not approved or tested this so it would be best to run a dedicated ground and feed directly from the TV battery. Many modern systems will model the battery SOC or can also measure it through an open voltage check in addition to using a current probe during operation to monitor useage. So the OEM system is designed to be operating directly to and from the TV battery. There are almost infinite ground locations for components throughout the system, but each of these are signed off by the design responsible engineer. If in doubt, and without having engineering approval, run both leads directly to the TV battery.

          Jim
          Thanks Jim for the clarification. I had read about chassis grounding to save negative cable, but if the ground through the king pin is interrupted (which easily could happen), it all goes through the 7 wire plug and truck wiring - not good in my mind.

          For my 60A install I am planning to run two 2 AWG (+/-) from battery (100A circuit breaker as close to battery as possible on +), or one of those stud fuses discussed earlier. I will be running a 2 awg negative too. Both will go full length to trailer (no separate grounding to truck frame). from the Renogy 60A output, both will tie into the power in bar. The negative side of this bar as you know from my install is tied to the trailer frame. One outstanding question is should I add a circuit breaker on the positive Renogy output side - say 70A just in case the unit goes bonkers? There will be a 200A solenoid in the positive line near the battery connected to an up fitter switch. At the trailer I am trying to decide if I want activation using running lights, or just tie to the 12V input so when truck power is present it turns on.

          Am I thinking correctly? Now to figure out the stud size at the battery - I think it is 10MM from what I can find.

          Thanks

          Happy Holidays
          Keith
          2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

          Comment


          • #80
            Originally posted by Yoda View Post

            Thanks Jim for the clarification. I had read about chassis grounding to save negative cable, but if the ground through the king pin is interrupted (which easily could happen), it all goes through the 7 wire plug and truck wiring - not good in my mind.

            For my 60A install I am planning to run two 2 AWG (+/-) from battery (100A circuit breaker as close to battery as possible on +), or one of those stud fuses discussed earlier. I will be running a 2 awg negative too. Both will go full length to trailer (no separate grounding to truck frame). from the Renogy 60A output, both will tie into the power in bar. The negative side of this bar as you know from my install is tied to the trailer frame. One outstanding question is should I add a circuit breaker on the positive Renogy output side - say 70A just in case the unit goes bonkers? There will be a 200A solenoid in the positive line near the battery connected to an up fitter switch. At the trailer I am trying to decide if I want activation using running lights, or just tie to the 12V input so when truck power is present it turns on.

            Am I thinking correctly? Now to figure out the stud size at the battery - I think it is 10MM from what I can find.

            Thanks

            Happy Holidays
            Keith
            Keith,

            Yes using a fuse or circuit breaker as close to the source (your TV) will protect the system all the way back to the Renogy. I wanted to also protect the outgoing circuit as well so I installed an inline fuse on that circuit in the trailer. Ford may provide lugs to connect your cabling where its always best to check with the OEM in making these connections. I'm certainly no EE but have worked as a systems engineer where we integrated with everything electrical and mechanical in the vehicle. With steering assist, braking assist, throttle by wire, adaptive cruise and even self driving trucks on the way, its important to make connections that will be approved by manufacturers.

            Jim

            Comment


            • #81
              Originally posted by Yoda View Post

              One outstanding question is should I add a circuit breaker on the positive Renogy output side - say 70A just in case the unit goes bonkers?

              There will be a 200A solenoid in the positive line near the battery connected to an up fitter switch. At the trailer I am trying to decide if I want activation using running lights, or just tie to the 12V input so when truck power is present it turns on.

              Happy Holidays
              Keith
              I’m not sure if the fuse/circuit breaker on the tow vehicle will trip if there’s an overload on the output side of the DC-DC charger, so a 70 amp breaker on the output of the charger couldn’t hurt. I have one.

              One thing your post doesn’t mention is a switch to control whether the charger outputs 30 or 60 amps. I have one. If I know I’m going to be driving 5 hours and know that 30 amps of charging will get me fully charged during the drive, I like the idea of limiting the charging to 30 amps over a longer period of time. Of course, if you charge at 60amps, the charger will stop outputting current when the batteries are fully charged. But I like the idea being able to control the charging rate, even though I have a new Mechman 320 amp alternator on my truck.
              Home Base: Fairfax, Virginia
              2021 Grand Design Reflection 315RLTS Travel Trailer
              2002 Ford F350 7.3 Diesel 4X4 SRW

              Comment


              • #82
                Yoda Keith, I think in the reference to using frame grounding on the TV is to minimize the need for the extra 12V- cable from the battery all the way back to the trailer.

                As I do not have a DC-DC charger and have never installed one, this is my understanding of how connecting it would be: I would do the frame as the 12V- (adding an additional cable from battery to frame) then to protect the wiring in the 7 way, dedicated 12V+ and 12V- to the input of the DC-DC charger. This way if something happens to either of the connections, the charger looses power and shuts off.
                Joseph
                Tow
                Vehicle: 2024 GMC K3500 Denali Ultimate Diesel
                Coach: 303RLS Delivered March 5, 2021
                South of Houston Texas

                Comment


                • #83
                  Originally posted by Jimmer View Post

                  I’m not sure if the fuse/circuit breaker on the tow vehicle will trip if there’s an overload on the output side of the DC-DC charger, so a 70 amp breaker on the output of the charger couldn’t hurt. I have one.

                  One thing your post doesn’t mention is a switch to control whether the charger outputs 30 or 60 amps. I have one. If I know I’m going to be driving 5 hours and know that 30 amps of charging will get me fully charged during the drive, I like the idea of limiting the charging to 30 amps over a longer period of time. Of course, if you charge at 60amps, the charger will stop outputting current when the batteries are fully charged. But I like the idea being able to control the charging rate, even though I have a new Mechman 320 amp alternator on my truck.
                  Jimmer,

                  I have a little 20amp unit where I trigger it with the trailer lights. I have also installed an output inline fuse. A separate switch could certainly be wired to cut the charge rate in half on the Renogy if there is a need for that.

                  Jim

                  Comment


                  • #84
                    Originally posted by Jlawles2 View Post
                    Yoda Keith, I think in the reference to using frame grounding on the TV is to minimize the need for the extra 12V- cable from the battery all the way back to the trailer.

                    As I do not have a DC-DC charger and have never installed one, this is my understanding of how connecting it would be: I would do the frame as the 12V- (adding an additional cable from battery to frame) then to protect the wiring in the 7 way, dedicated 12V+ and 12V- to the input of the DC-DC charger. This way if something happens to either of the connections, the charger looses power and shuts off.
                    Joseph - you just confused me - but that is easy to do. You seem to imply I don't need to run a 12V negative from the battery back to the 5th wheel - but I think I do.

                    Truck - battery is already grounded to the frame, so no need for anything there.

                    Trailer also has a frame ground, both from the battery and a second one separated by several feet from the Multiplus. There is a third ground bar on the frame for all the stock 12V wiring and I believe one for the 120 V from the distribution panel (could be wrong on that - may just be to the shore power ground.

                    The only direct continuous ground between the two is through the 7 pin plug. I say continuous as there is possible grounding between the frames (truck and trailer) through the 5th wheel king pin (ball connection for TT) The 7 pin plug is either 10awg or 12 awg, so not good for much amperage.

                    To me with the 60 amp Renogy unit pulling close to 90 amps from the truck batterys, I need seperate dedicated wire runs - both positive and negative, fused and insulated to protect the truck and trailer wiring should a short occur. Using the truck frame could easily result in wiring damage. Eve if I do a frame to frame ground strap 2 awg or better between the truck and trailer, there is a chance if it came loose thing could get hot fast.

                    I think I will stay with 2 separate 2 awg wire runs for the truck to the trailer - one positive (fused/relay) and 1 negative.

                    I do appreciate your input and if I miss understood what you said, please let me know. We all know here I never make a mistake

                    Thanks Keith


                    2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

                    Comment


                    • #85
                      New question for the electrical folks - ON/OFF isolation solenoid so circuit is only hot when I want it to be

                      I am planning to use a 200 A continuous duty solenoid like the following. Many of the builds use something similar. This is a USA based brand (Littlefuse / Cole-Hersee), US customer service, made in Mexico from what I can tell
                      https://www.amazon.com/Cole-Hersee-2...NsaWNrPXRydWU=

                      However it has no IP rating.

                      Littlefuse, parent of Cole Hersee, does in fact make an IP 66 rated version of this unit with a potted coil for vibration resistance. Its model 24213-01
                      https://www.littelfuse.com/products/.../24213-01.aspx
                      Model line up at bottom of this page
                      https://www.littelfuse.com/products/...duty-spst.aspx
                      medial sheet
                      https://www.littelfuse.com/media?res...duty-datasheet

                      Given the rough environment in the truck bay would it be prudent to get the IP66 potted coil unit, they are running about $90 -$100 and tough to find. I want something dependable, or for the money get two of the stock units, just in case?

                      I am planning to fully document my build when it happens

                      All thoughts are welcome

                      Thanks
                      Keith
                      2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

                      Comment


                      • #86
                        TravelHabit

                        I will second the request for your post on your install. Please start a new thread with the post , it is always great to see another "way" for an install.

                        Brian
                        Brian & Michelle
                        2018 Reflection 29RS
                        2022 Chevy 3500HD

                        Comment


                        • #87
                          Yoda Keith, What I am implying is that there is enough material in the frame of the truck to pass the required 12V- current sufficiently. Basically put a short 12V- from the battery to the frame then a short 12V- from the frame to the PowerPole connector. This will help minimize the copper runs from the battery to the back of the truck. The 7 wire is most likely done this way. Common ground point used for probably something like 3-5 systems.

                          Then from the PowerPole on the truck there are 2 dedicated runs to the DC-DC charger. That way if anything happens to the PowerPole connector, the charger looses supply and shuts off before it can overheat the 7 pin wiring. This also eliminates the possibility of having intermittent connection issues thorough the king pin.
                          Joseph
                          Tow
                          Vehicle: 2024 GMC K3500 Denali Ultimate Diesel
                          Coach: 303RLS Delivered March 5, 2021
                          South of Houston Texas

                          Comment


                          • #88
                            One last word of advice for those that really want to ground to the chassis. Since your current main battery ground connection is most likely bolted to the engine block for starting and charging functions be sure there is a properly sized ground path from the chassis to the engine block that can handle these loads. Secondary systems may have an alternate ground path other than the engine block depending how the TV is wired.

                            Jim
                            Last edited by Guest; 11-27-2021, 10:10 PM.

                            Comment


                            • #89
                              Originally posted by Jlawles2 View Post
                              Yoda Keith, What I am implying is that there is enough material in the frame of the truck to pass the required 12V- current sufficiently. Basically put a short 12V- from the battery to the frame then a short 12V- from the frame to the PowerPole connector. This will help minimize the copper runs from the battery to the back of the truck. The 7 wire is most likely done this way. Common ground point used for probably something like 3-5 systems.

                              Then from the PowerPole on the truck there are 2 dedicated runs to the DC-DC charger. That way if anything happens to the PowerPole connector, the charger looses supply and shuts off before it can overheat the 7 pin wiring. This also eliminates the possibility of having intermittent connection issues thorough the king pin.
                              Now I understand. Anyway before your post I already got my wire ordered. Best price I could find Free shipping and no tax.
                              https://temcoindustrial.com/temco-wc...awg-50-ft-red/
                              https://temcoindustrial.com/temco-wc...g-50-ft-black/

                              One thought
                              With the new truck too as the body is aluminum and frame steel I need to be careful not to change up the balance. I know they have anti- corrosion measures of some kind. There is a lot to learn about the proper fasteners to use just to connect to the body. I believe stainless steel is the way to go, but need to read more. Ford.com has some information on it and in the builders guides.

                              Thanks again for explaining - makes sense.
                              Keith
                              2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

                              Comment


                              • #90
                                Originally posted by Country Campers View Post
                                TravelHabit

                                I will second the request for your post on your install. Please start a new thread with the post , it is always great to see another "way" for an install.

                                Brian
                                You do know what your asking for? Remember my initial inverter /charger project that turned into a Multiplus install which howson Howard recommended in the first place - but I knew better ? Just be sure to laugh at me.
                                Keith

                                Your safe until spring I think - still no word on a production date on the order.
                                2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

                                Comment

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